A spectacle lens edging apparatus generally includes a lens holding shaft and processing tool rotating shaft. An uncut round lens (to be also referred to as a processing target lens hereinafter) is mounted on the lens holding shaft through processing jig tools (a lens holder and lens retainer). A processing tool such as a grinding wheel attached to the processing tool rotating shaft processes the circumferential surface of the processing target lens, thus forming the lens into an edged lens shape complying with the frame shape of the spectacle frame. The lens holding shaft has first and second lens holding shafts arranged coaxially. The lens holder and lens retainer respectively attached to the opposing end faces of the first and second lens holding shafts sandwich the processing center portion of the processing target lens.
As a lens holder used in such an edging apparatus, for example, lens holders disclosed in, e.g., Japanese Utility Model Laid-Open No. 6-24852 and Japanese Patent Laid-Open Nos. 2001-47347 and 2005-271203 are known.
The lens holder described in Japanese Utility Model Laid-Open No. 6-24852 includes a clamp shaft attached to a lens holding shaft, and an elastic seal for holding the convex optical surface of a processing target lens. Sawteeth are formed on the seal attaching surface of the clamp shaft and caused to bite into the elastic seal, so that axial deviation of the processing target lens caused by the processing resistance generated during edging is prevented.
In the lens holder described in Japanese Patent Laid-Open No. 2001-47347, small recesses and projections are formed on a lens holding surface having a convex spherical shape which is to come into tight contact with the convex optical surface of a processing target lens, in the same manner as in the lens holder described in Japanese Utility Model Laid-Open No. 6-24852 mentioned above, in order to increase the tight connecting force with respect to an adhesive pad. The small recesses and projections have V-shaped sections in each of which the wall surfaces on the front and rear sides in the rotational direction are formed of surfaces inclined at almost the same angle. With this lens holder, since the adhesive pad evenly comes into tight contact with the two slopes of each of the small recesses and projections, the contact area enlarges to increase the lens holding force. Since the adhesive pad evenly comes into tight contact with the two slopes, no extra rotating force is generated in the adhesive pad. Thus, axial deviation of the processing target lens can be prevented.
The lens holder described in Japanese Patent Laid-Open No. 2005-271203 also includes teeth having V-shaped cross sections, in the same manner as the lens holder described in Japanese Patent Laid-Open No. 2001-47347 mentioned above.